1. Field of the Invention
The present invention relates to a wired circuit board. More particularly, the present invention relates to a wired circuit board for mounting an electronic component, such as a suspension board with circuit.
2. Description of Related Art
A wired circuit board such as a suspension board with circuit includes, for example, a metal supporting board of stainless steel foil or the like, an insulating base layer of polyimide resin or the like, which is formed on the metal supporting board, a conductive pattern of copper foil or the like, which is formed on the insulating base layer, and an insulating cover layer of polyimide resin or the like, which is formed on the insulating base layer to cover the conductive pattern. The wired circuit boards of this type are widely used in a variety of fields of electric and electronic equipment.
In such wired circuit board, in order to prevent electronic components mounted thereon from electrostatic breakdown, there has been proposed that a semiconductor layer is formed by sequentially laminating a metal thin film and a metal oxide layer on surfaces of the insulating cover layer or insulating base layer of the suspension board with circuit, so that electrostatic charging can be removed via the semiconductor layer (cf., Japanese Unexamined Patent Publication No. 2004-335700).
In addition, there has been proposed that after a semiconductor layer is formed on a surface of an insulating layer, a through hole extending through the insulating layer and the semiconductor layer is formed so that a conductive layer may be exposed, and a connecting terminal is formed in the through hole to contact the semiconductor layer with the connecting terminal, thereby removing static electricity charged on the insulating layer and the conductive layer (cf., Japanese Unexamined Patent Publication No. 2003-152383).